Did the cars in the 50s and 60s get 30 MPG ?
I had a 1969 Saab 96 that had a Ford V-4 and 4 in the tree. It got 38 mpg highway and had crazy power! (I lived in the mountains in Co.)
It also had a thing they called a 'free wheel clutch' that allowed the car to glide instead of slowing down when you let off the gas. I think the are now implementing this in newer auto transmissions.